HP 6125XLG R2306-HP 6125XLG Blade Switch Layer 3 - IP Services Configuration G - Page 69

Configuring a DHCP client ID for an interface, Enabling duplicated address detection

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Configuring a DHCP client ID for an interface A DHCP client ID is added to the DHCP option 61. A DHCP server can specify IP addresses for specified clients based on the DHCP client ID. Make sure the IDs for different DHCP clients are unique. To configure a DHCP client ID for an interface: Step 1. Enter system view. 2. Enter interface view. 3. Configure a DHCP client ID for the interface. 4. Verify the client ID configuration. Command Remarks system-view N/A interface interface-type interface-number N/A dhcp client identifier { ascii string | hex string | mac interface-type interface-number } By default, an interface generates the DHCP client ID based on its MAC address. If the interface has no MAC address, it uses the MAC address of the first Ethernet interface to generate its client ID. display dhcp client [ verbose ] [ interface interface-type interface-number ] DHCP client ID includes ID type and type value. Each ID type has a fixed type value. You can check the fields for the client ID to verify which type of client ID is used: • If an ASCII string is used as the client ID, the type value is 00. • If a hex string is used as the client ID, the type value is the first two characters in the string. • If the MAC address of a specific interface is used as the client ID, the type value is 01. Enabling duplicated address detection DHCP client detects IP address conflict through ARP packets. An attacker can act as the IP address owner to send an ARP reply, making the client unable to use the IP address assigned by the server. HP recommends you to disable duplicate address detection when ARP attacks exist on the network. To enable duplicated address detection: Step 1. Enter system view. 2. Enable duplicate address detection. Command system-view dhcp client dad enable Remarks N/A By default, the duplicate address detection feature is enabled on an interface. 60

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60
Configuring a DHCP client ID for an interface
A DHCP client ID is added to the DHCP option 61. A DHCP server can specify IP addresses for specified
clients based on the DHCP client ID.
M
ake sure the IDs for different DHCP clients are unique.
To configure a DHCP client ID for an interface:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter interface view.
interface
interface-type
interface-number
N/A
3.
Configure a DHCP client ID
for the interface.
dhcp client identifier
{
ascii
string
|
hex
string
|
mac
interface-type
interface-number
}
By default, an interface generates
the DHCP client ID based on its
MAC address. If the interface has
no MAC address, it uses the MAC
address of the first Ethernet
interface to generate its client ID.
4.
Verify the client ID
configuration.
display dhcp client
[
verbose
]
[
interface
interface-type
interface-number
]
DHCP client ID includes ID type
and type value. Each ID type has a
fixed type value. You can check the
fields for the client ID to verify
which type of client ID is used:
•
If an ASCII string is used as the
client ID, the type value is 00.
•
If a hex string is used as the
client ID, the type value is the
first two characters in the string.
•
If the MAC address of a specific
interface is used as the client
ID, the type value is 01.
Enabling duplicated address detection
DHCP client detects IP address conflict through ARP packets. An attacker can act as the IP address owner
to send an ARP reply, making the client unable to use the IP address assigned by the server. HP
recommends you to disable duplicate address detection when ARP attacks exist on the network.
To enable duplicated address detection:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enable duplicate address
detection.
dhcp client dad enable
By default, the duplicate address
detection feature is enabled on an
interface.